With this change we can remove all the old trap code.

R=titzer@chromium.org, clemensh@chromium.org

Change-Id: I85c10a6ac7d3eccc7b611e06f2a651d5a8a00a9c
Reviewed-on: https://chromium-review.googlesource.com/452379Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43853}